Transmission mechanism



. y? 1 f v l W June 5, 1928. 1,672,368

G.' C. CARHART TRANSMISSION MEGHANWISM Filed Nov. 22, 1925 3 Sheets-Sheet 1 June 5, 1928.

G. c. cARHAR-r TRANSMISSION MECHANISMv Fil'ed Nov. 22, 1923 ATTORNEYS.

3 Sheets-Sheet 2 INVENTOR.

. June 5, 192s. '1,672,368

' G. C. CARHART TRANSMISSION AMECHANI SM I N VENT 0R.

Patented June 5, 1928.

UNITED STATES PATENT OFFICE.

GEORGE C. CARHART, OF SYRACUSE, NEW

YORK, ASSIGNOR TO yIBROVTN-LIPE GEAR COMPANY, F SYRACUSE, NEW YORK, A CORPORATION OF NEW YORK.

TRANSMISSION MECHANISM.

Application 'led November 22, 1923. Serial No. 676,444.`

This' invention relates to transmission` mechanism, particularly of the type used in motor vehicles, and has for its object an especially simple compact, durable and eii-4 cient secondary clutch, for transmitting the motion to the driven shaft of the variable speed gearing or the driven shaft section connected to the propeller shaft of the'vehicle, which clutch 1s operable in conjunction with the main or engine clutch in such manner that the transmission gearing is disconnected from the propeller shaft during gear shifting operations, the secondary clutch being of such l5 engaged and disengaged after. and before each gear shifting operation with out shock or jar irrespective of the personall equation 'of the operator and irrespective of the m0- mentum of the rotating parts of the gearing,

or of the propeller shaft due to the momen-h tum of the vehicle.

rlhe invention consists in the novel features andin the combinations and constructions hereinafter set forth and claimed.

In describing this invention reference is had to the accompanying drawings in which like characters designate corresponding parts in all the views.

Figure l is a fragmentary, vertical sectional view of a transmission mechanism showing the secondary clutch mechanism and the contiguous portion of the transmission gearing.

Figure 2 is a sectional View taken on the plane of line 2-2, Fig. 1.

Figure 3 is a sectional view taken on the plane of line 3 3, Fig. l.

Figure 4 is a planview of the key for locking one of the 40 driven shaft, for transmitting the drive in one direction. i

Figure 5. isa view of the other key simim lar to the View shown in Fig. 4, for transmitting the drive in the other direction.

Figure 6 is an elevation of the key shown in Figure 5.

Figures 7, 8, and 9 are views similar to Figs. 4,. 5, and 6, of the right' and left keys for transmitting the motion between the driven.' shaft and the clutch section, which is rotatably mounted on the driving shaft. l

`Figure 10 is an end elevation of the key shown inFigli, and is an illustrative end construction that it is clutch sections to the elevation of the key shown in Figs. 5, 7 and 8.

Figure 11 is a diagrammatic view of the entire transmission mechanism including the main clutch between the engine, and the transmission caring, the operating lever for the vsecon ary clutch at the rear of the transmission gear and the connections between the operating means for such clutches.

In transmission gearin s, such as are used in motor vehicles, in shi ting the gears the main or engine clutch is first thrown off by depressing the clutch pedal and then the gear shifting lever operated, and vafter the shifting is completed vthe engine clutch 1s again engaged by releasing the clutch pedal. lf the gears which are to be meshed are not rotating 'at approximately speed the gears will clash instead of meshing and the operator must either wait until the movements of the gears synchronize or in case of shifting from a high to a lower speed, the operator must again let in the clutch and speed up the engine until the speed of the transmission gears are synchronized.

Such operation requires skill and. in some situations 1t 1s lmpossible for the ordinary operator, and with many drivers gear shif ing is a hit or miss affair.

Secondary clutches have been employed to disconnect thetransmission gearing from the propeller shaft of the vehicle, during the gear shifting operations in order that lthe gears can not only be disconnected from the engine but also from the propeller shaft of the vehicle in order that the gears may be -practically idle during the gear shifting operations. Jaw clutches used to disconnect the driven shaft of the gearing during the gear shifting operations and to connect the shaft after the gear shifting operation are liable to and usually do engage with a shock, jar or-'noise, when the main clutch is engaged. Such shock and ar is due to the fact'that the momentum o the vehicle is not` synchronized with the speed of the engine, so that either the gears are rotatingfaster than the driven shaft or the driven shaft is belng rotated by the momentum of the vehicle faster than the gears of the gearing. When friction clutches, disk clutches, etc.,"have been used the same shock and jar usually takes place owing to the fact that a' nice .adjustment of the friction faces cannot be made sothat the same the clutch will not grab or 'take hold too soon and any adjustment is more or less a hit or miss affair, and furthermore the friction of such friction clutches when fully yengaged must be equal to r greater than the friction of the main clutch, it being understoOd that the 'main clutches are of some friction type. In other words the frictional engagement of the secondary clutch at 'there-ar end of the transmissionV must be sufficient to transmit the maximum torques at all times without slipping and must be capable of slipping without grabbing after each gear shifting operation to permit the clutch to engage without jar or shock after each gear shifting operation. It is extremely difficult if not impossible to combine a main' clutch and aV secondary friction rear clutch which will transmit the maximum and varying torques without slipping and at the same time easily engage vto eliminate shock and jar, without grabbing or taking hold too soon, that is, to combine with the main clutch, a secondary clutch that will compensate or equalize for the variations between the momentum of the vehicle and the speed. of the engine.

My invention has for its object a construction or combination of such secondary clutch with a main clutch of the vehicle,

, whereby the secondary clutch will engage -`other of which sections is mounted on the latter or driven shaft to' rotate about thel driving verse order. hat is theo the other member or drivenshaft, and the same, and means operable (when operated -to successively lock the frictlonmally 'engaged sections to the latter member or'driven shaft' and successive] unlock the same in the rerating means operates first to lockthe clutc section rotat-l ably mounted on the drivenmember orshaft and disconnected .fromthe driving shaft lll) except for the friction between the friction faces of the clutchv sections lso that the motion is first transmitted from one Asection 'tol the other through a friction driv and the operating means thereafter operatesto positively lock the section secured `to the riving member or .shaft to the driven shaft. And in addition vtheinvention includes a connection ,between the operating shaft and rotatable relatively to| 'i the art; The I intermediate of the shaft 3 and its rear end in a friction of the frictionally engaged sections y and thereafter the other section disengaged or unlocked, from the driven shaft, so that,

the gearing. is entirely free of the engine,

and the propeller shaft of the vehicle and the gears can come to a stop or nearly to al stop preliminary to the `gear-shifting operation; tand whereby after the gear shifting operation is completed the main clutch pedall is released to engage the main clutch, and 'thereafter the frictionally engaged clutch sections locked to the driven shaft, so that, the drive is first through the frictionally engaged clutch sections and the rotation of the driving and thereatfter the clutch section'which is permanently secured to the driving shaft is locked to ythe driven shaft, so that the friction is not relied upon to (transmit the motion between the driving and driven shafts. e

In its entirety this 'transmission mech- I,and driven shafts eqwalized,

anism comprises driving, driven and intermes diate shafts 1, 2 and 3the intermediate shaft being the direct driver for the driven shaft, a counter -shaft 4 supported in a suitable casing 5', changespeed gearing between the driving shaft 1, the countershaft d andthe intermediate shaft 3; a main 'clutch2 6 for connecting and disconnecting the drive shaft from the engine of the vehicle and a second- .ary vclutch 7 between the intermediate shaft 3 and the driven shaft 2 operating inconjunction with the. main clutch. The driving, driven and' intermediate shafts are prefer- 4*ably arranged in axial alinement lin'the ordinary transmission gearing. f, this type. The 'shaft 2 is the driven shaft connected di reet-lyJ l to" the propeller shaftA through a universal Joint."

f1 In my transmission mechanismsthe driven shaft 2 is practically a section of the interlll) mediate sha 3 or what is the driven shaft' A in thejrdi ary transmission gearing. Ther driven shaft or shaft section 2 is lconnected to the propeller shaft in any well known` manner, usually as will be understood b v those' familiar-with' y shaft 3 is journalled at its front endin abearing'in the innerendof 'the shaft 1 and at its rear end in'a bearing 13, in the rear wall of the case' 5. 4 f h The; drivenmshaft or shalt'section 2 is jpurnalled at its front end at 1:1 in the rear end bearing through a` universal joint,

15 mounted in the rear end Wall of the casing 16 for the secondary clutch which casing is detachably mounted on the rear end wall of the casing 5. The conntershaft 4 is also journalled in suitable bearings in the end Walls of As the main clutch 6, may be :of any suitable form, size and construction, description thereof is thought .to be unnecessary. It is suflicient to bear in mind that suchl clutch includes an aXially shiftable member operating a disk or disks this member being oper ated by a collar 32, Fig. 11', which collar is moved 'in one direction to engage the clutch by a powerful springand in the other direction by a. yoke 33 which is operated by a clutch pedal 34.

rlhe secondary clutch comprises frictionally engaged clutch sections 35, 36, one of which as section 35` is secured to the intermediate shaft 3 or the driving shaft for the driven shaft 2, to rotate therewith, and the v other of which as 36 is mounted on the shaft 2 to rotate about the same, the section 36 also having a portion'enclosing the periphery' of theshat't 2, and means o )cr-able when operated for successively locking the sections 36 and 35 -to the shaft 2 when operated in one direct-ion and successively unlocking the sections 36 and 35 from the shaft 2 in the reverse order, that is, first unlock the section and then the section 36. The sections 35 and ,36. are here shown as provide-d with conical friction surfaces at,37 andthe section is shown as formed integral with the shaft 3. The section 36 is yspring pressedto constantly, yieldingly and rictionally engage the conical surfaces 37 and there,v is no operating means for shifting the sections 35, 36 apart. lAs here illustrated, the section 36 is constantly pressed toward the section'35 by a series of springs 38 located in suitable recesses 39 in the rear face' lof the section 36 and thrustingat like ends against the bottoms of the recesses and vat their v against an abutment ring 38a. The abutment ring thrusts against an annular plate' 40 at the rear end of a cylindrical housing 41 enclosing the clutch sections u 35and 36 .f and interlocked with the clutch section 35,

with'tong-ues 45 a` split resilient `locking ring 46 is sprung it being 'formed with an irl-turned annular flange42 atA its front end abutting- .against the rear face .of the section 35.' The rin or plate 40 is interlocked to the rear end o `the housing 41 by any suitable meansand, as here illustrated, the housing 41g at its rear edge is formed with notches-43 and .with in-turned. lips 44, formed by an `internal annular groove,

fitting into the notches ,and

'i into the groove against therear side of the plate 40 and behind thelips 44.

The meansV for lockingJhe sections 35 Aand the case 5 parallel to the interme- -diate shaft 3.

other ends the -plate 4Qk being formedv 2, are referred toas short keys 36 to the shaft 2 comprisesl a key operating a key operating' to lock the section 35 to the sha-ft, the keys being normally arranged within the periphery of the shaft 2 and being shiftable to l'n'ojectportions thereof above said periphery into interlocking e11- gagement with the walls of the bores of the sections 36 and 35. Preferably a pair of keys are employed to lock the section 36 to the Shaft 2 and also another pair of keys to lock the section 35 to the shaft. key of each pair serves to transmit motion in one direction and the other key of each pair to transmit motion or the torque in the other direction, the keys of each pair being reversely arranged. i50 and 51 designate keys for 2, and 52 and the pair of keys for lockingthe clutch section 35 to the shaft 2. These keys, as shown in Figs. 3 to l0 inclusive, are rounding or arc-shaped in cross section and 'tit inl lengthwise arc-shaped grooves or channels 54t'ormed in the shaft 2 and are rorkable about their axes in the channels to project portions as shoulders 55 and 56 on the keys 50 and '51e and shoulders 57 and 58 on the keys 52 and 53 respectively above the periphery of the shaft 2"into recesses 59 and 60 within the bores of the 4clutch sections 36 and 35.

One

'to lock the section 36 to the shaft and alsoy locking section 36 to the shaft.

Obviously, upon the rocking of these keys abdut their axes in one direction to projectl the shoulders .55r and 56 of the keys 50 and 51 above theperiphery ofthe shaft 2, such shoulders will enter a diametrically opposite pair of notches 59 in the clutch section-3`6,

so that rotation of the clutch section 36 to theright, Fig. 3, willbe transmitted to the shaft 2, through the key 50 and, rotation of the vclutch section to, the left willbe transmitted through .the shoulder 56 of the key 51 to the shaft 2, also any driving force of the shaft 2 when the shaft 2 is being driven b themomentum of thefvehicle will be trans erred from the shaft 2 to`-the clutch -section 35 through the shoulder 1,57 of the key 52. h L

The keys 50, 51 and 52, 53 are preferably 'of the same length, but forlconvenience the keys `v5.0, 51, which serve to lock the clutch section 36 nearest the collar l61, to the shat as the need not be as long as the keys 52, 53 and1 their iso projecting portions or shoulders 55, 56 are located nearer the right hand ends of such keys than the shoulders 57, 58 of what for yconvenience are called the long keys 52,53.

- That is, the keys and 51 are short keys for the reason that their active portions or shoulders 55, 56 are located nearer one end, asthe right -hand end of the keys, than the active portions or shoulders I57` 58 of the ,ke s,4 52, 53.

he means for shifting the keys 50, 51 and 52, 53 abouttheir axes in the channels 54 comprises a collar or sleeve 61 shiftable axially of the shaft 2 and of the keys into and outof engagement with oppositely inclined Acam faces on each kym opposite sides of its longitudinal axis, and on opposite sides of the `collar 61. 62 and 63 designate' the oppositely inclined cam faces on opposite sides of the axis of the short keys 50 and 51 which coact with the lclutch section 36 and 64, 65 designate the oppositely inclined cam faces on the long .keys which coact with the clutch section 35, these cam faces being so inclined and spaced apart lengthwise of the keys and being located on I y yopposite sides of the longitudinal axes of the ders 55, 56 and 57, 58 beyond the peripheryl keys, that When'the collar 61 is shifted in one direction as to the left, Fig. 1, it en- Vgagesthe inclined faces 62, 64 of the keys 50, 51 and 52,- 53, and the keys will be rocked to project their high points or shoulof theshaft 2, and when the collar is shifted in the other direction as to the right, Fig. 1,

a `and engage4 thel cam faces 63, 65, the keys will be'rocked in the opposite direction to 64 and 65` of the long keys are lspaced a art the same distance apart as the cam aces 62, 63 of the short keys but'the faces 62l of the short keys and the faces 65 of the long keys are arranged nearer the left and right ends of the collar 61 than the corresponding faces 64, of the long keys andfaces 63 of the short keys, so that, the faces 62 of the l .short keys and 64 of the/long keys are successively engaged by the collar` 61 when shifted to the left, and the faces 65 of the long keys and 63 of the short keys are successively engaged by the collar 4when shifted .to theright. Therefore, assuming that the clutch sectiohs 3.5, 36 are locked to the shaft 2,. upon shifting o f the collar 61 to the right, Fig. 1, the collar will firstc enga e the cam faees'65- of the long keys and r Y saidv the the collar 61 when shifted to the left first engages the cam faces 62 of the short keys 50 and 51 and rocks them to interlock with the clutch section 36, so that, the torque between the sections 35 and 36 is transmitted through the conical friction surfaces 37 giving the motion between the intermediate shaft 3 and driven shaft 2 time to equalize; and thereafter the collar 6l engages the cam faces 64 of the long` keys 52, 53 and rocks them in their channels to interlock with the section 35. During'Y the period that the torque is transmitted through the conical friction faces, the motions between the shafts 2 and 3 is4 synchronized before lthe shaft 3 is positively locked to the shaft 2 by operation of the long keys 52, 53. As the rotary motion of these shafts is substantially synchronized, there isno attendant shock or jar or noise. j

Furthermore, owing to the rocking movement of the keys there is no pumping action nor any lretarding ofthe operation thereof, due to a plungereffect of sliding keys in the channels which may be filled with oil.

The collar 61 is operated by a suitable fork 66 working in a groove 67 in the collar 61, this fork being mounted upon a rock shaft 68 journalled inthe cover 69 of the case 16, this rock shaft having a leverarm 70 at its outer end which is connected by a link 71 to the clutch pedal lever 34. 1 n

The casing 16 is detachably mounted on ,the rear wall of the case 5 and, as here shown, is provided with a flange 72 secured to the rear wall of the casing 5 in any suitable manner as by cap screws 73. Thus the secondary casing with its housing can be attached and removed as a .unit to and from the gear casing 5. v

In operation, when the clutch pedal 34is depressed, the rock shaft 68 is also actuated to shift the collar 61 to the right and thus first operate the keys 52, 53 to release the clutch section 35 from theshaft 2 and thereafter to operate the keys 50, 51 and release the clutch section 36, so that the intermedi- `ate shaft 3 and countershaft 4 and also the driving shaft is disconnected from all forces tending to turn them and hence the shifting Aof the gears of the change speed gearing takes place either when the gears are rotat- 1n drigving them or when they are idle. After ears have been shifted and the clutch pedalever 34 is released to allowthe clutch very slowly and without any power v nize, or if the shaft 2 is shaft 2 during spring to engage the main clutch, the rock shaft 68 is also operated to shift the collar 6l to the left, first operating the short keys 50, 51 to lock the clutch section 36 to the shaft '2, so that either the shaft 3 drives the shaft 2 through the frictionally engaged sections 35, Stand, if their rotation is not the same. permits their rotation to synchroacting as a driver, due to the momentum of the vehicle, also permits the rotation of the shafts to equalize through the frictionally engaged sections 35, 36. When the synchronization is effected, the collar 6l acts to engage the cani surfaces 64 of the long keys and operates the long keys 52, 53 to positively connectthe clutch section to the shaft 2, the interval between tlie operation of the short and long keys 50, 51 and 52, 53 being sufficient to give the frictionally engaged clutch sect-ions 35, 36 time, to synchronize the rotation of the shafts, 2, 3. p

ly reason of the constantly and yieldingly frictionally engagedclutch sections 35,36 being entirely disconnected from the driven the gear shifting operation and also by reason of the friction between the sections 35, 36 being constant and predetermined, and not dependent in the least on the skill of the operator and further owing to the successive interlocking lof the sections 35, 36 with the shaft 2, so that an` interval is provided for a slipping and synchronizing of the sections through constantpre-determined-frictionally engaged sections,

the transmission gearing can'be connected to the propeller shaft of the vehicle Without shock or jar following the gear shifting operation or following any .time when the main clutch is thrown off and again let in without shifting the gears, as for instance,

when the vehicle is coasting down a hill or on a level with anyone of the shiftable gears iii its engaged positions and with the vinain clutch thrown out, and letting in-tlie main clutch at the approach of the foot'of the hill. Ordinarily, under such conditions the propeller shaft is rotating faster than tlievengine, and when the clutch is let in there is a violent jar due to the propeller shaft giving sudden impulse to the engine through the gearing. Such jars throw sildden strains on the gearing and on the splines and keys of the rear axle shafts, and tend to break them or develop looseness therein.

By my transmission mechanism, such violent shocksY and attendantevils are eliminat'ed. y

1. In a transmission mechanism, the combination of driving and driven shafts, frictionally engaged clutch "sections, one of which isl rotatably secured4 to one of said shafts `and encloses the other shaft, and the other of Which sections is rotatably'mounted `ing the othermember,

tween the latter shaft and the sections and extending into the bores thereof, and operable when actuated to successively lock the frictionally engaged sections to the latter shaft and successively unlock them in reverse oi'der.-

2. In a tiansmissionmechanism, the combination o-f driving and driven members, a pair of frictionally engaged clutch sections, one clutch section being secured to one inemportion of the other member, and the other section also surrounding a portion of the latter member, and rotatably mounted thereon, and mean operable. to successively lock saidclutch sections to the latter member.

3. The combination of driving and driven shafts, arranged in axial alinement, frictioiially engaged clutch sections, one section being secured to one of said shafts to rotate therewith, and the other section being rotatably mounted surrounding the other shaft, and shiftable means operable to connect both of said sections to such latter shaft.

4. The combination of driving and driven shafts, arranged in axial alinement, fraictionally engaged clutch sections, one section being secured to one of said shafts to rotate therewith, and the other section being rotatably mounted on the other shaft, and

shiftab'le means operable to successively connect the sections directly to such other shaft.

5. In a transmission mechanism, driving and driven shaftsarranged in axial alinenient, frictionally engaged clutch sections,

one section being secured to the driving shaft.

to rotate therewith, and having a portion enother secthe Adriven and shiftclosing the driven shaft, and the tion being rotatably mounted 'on shaft adjacent the former section,

able means operable to lock the sections directly to the driven shaft.

6.v In a transmission mechanism, thewcombination Pof driving and driven members,

on the other shaft and means interposed be- 'lisv 'ber to rotate therewith, and enclosing a llo engaged clutch sections having tate therewith, and shiftable means operable to successively lock the frictionally engaged sections tothe former member, and successively unlock such sections from the former member in the reverse order whereby the motion 'is first transferred through the frictionally engaged the other and thereafter transmitted directly from one 'member to the other.

ign

sections from either member to 7. In a. transmission mechanism, theicombination of driving and driven members, a

clutch section secured to one member to rotate therewith, and having a oi-tion enclosa secon clutch section rotatably mounted on irst disconnect the first section and therelclutch section mountedl on the after disconnect the second section from such latter member;

8. In a transmission mechanism, the combination of driving and driven members, a clutch section, secured to one member to rotate therewith, and having .a portion enclos-` ing the periphery of the other member, a second clutch section mountedon such other member to rotate relatively thereto, the clutch sections being frictionally engaged, and means normally arranged within the periphery of the latter member and yoperable when operated to project beyond the periphery thereof to lock bothl sections to such member. 1 v

9. In a transmission mechanism, the com'- bination of driving and driven members, a clutch section, secured to one member to ro` tate therewith, and having a portion enclosing the periphery of the other member, a second clutch sectionmountwed on such latter member to rotate relatively thereto, the clutch sections being frictionally engaged, and means normally arranged within the periphery of the latter member and operable when operated to project beyond such periphery to'lock both sections to the latter member, such operating means when operated in one direction acting first to connect the second clutch section to such latter member ,and thereafter connect the firstI clutch section to such latter member and when operated in another direction to disconnect vsuch sections from such latter member in the reverse ord'er.

10. In a transmission mechanism, driving and driven shafts, arranged inaxial alinement, a clutch section mounted on one shaft to rotate therewith, and enclosing the periph ery of a portion of the otherv shaft, a second latter shaft,

- and the clutch sections I in the bores thereof, t e grooves -being arc and. rotatable vrelatively thereto, the latter shaft being formed with len thwise grooves, rovi ed with recesses shaped and arc shaped" keys lying in the grooves normally below the periphery'of the latter shaft, and means for rocking the keys to project portions thereof above the periphery and into such recesses. I

11'. In a transmission gearing, the combination of a shaft, a pair of frictionally engaged clutch sections mounted on the shaft to rotate relatively thereto, the shaft being formed with two pairs of lengthwise grooves arc-shaped in cross section, and the lclutch sections being formed with recesses in the bores thereof, keys arc-shaped in cross section arranged in the pairs of grooves, and being mounted to rock therein, said keys being normally disposed below the periph# ery of the shaft and being movable to'pro- `ject portions thereof above the periphery of the shaft, the projections of one -pair of keys being arranged to interlock with the recesses of one clutch section, and the projections of the other pair of keys to interlock within the recesses of the other clutch section, the keys of each pair being reversely arranged relatively to each other one being right hand to transmit motion in one direction and the other being left hand to transmit motion in the reverse direction, each key being provided with reversely larranged cam faces spaced apart in the direction lengthwise of the key and located on opposite sides 'of the axis of the key, a sleeve slidable on the shaft and on the keys between such cam faces, the

cam faces of one pair of keys being arranged" out of circumferential alinement with the cam faces of the other pai'r of keys, whereby such pairs of keys are successively rocked in the grooves.

ln testimony whereof, I have hereunto signed my name, at Syracuse, of Onondaga, and State'of New York, this 20th day of November, 19:23.'

GEORGE o. CARHART.

in the county 

